For rough estimates of forced convection, AutodeskĀ® CFD will use the velocity potential equation to establish a quick baseline flow field that can be used for the advection terms in the energy (thermal) equation. The velocity potential equation replaces the Navier-Stokes equations. This equation can be written as:
where is the velocity potential defined as:
where is the velocity vector. The pressure is obtained using Bernoulliās Equation:
where is the density of the fluid.
After the velocity potential is calculated using the above equation, the velocities are calculated using
and pressure is calculated using
With these velocities, the energy equation (First Law of Thermodynamics described earlier) is solved for temperatures.